Toward the objective of cutting wide swaths of grass or other growing vegetation, overland traversible apparatus utilizes a plurality of side-by-side rotary blades adapted for simultaneously cutting vegetation and centrifugally discharging the cuttings through one or more tubular chutes. For grass cutting operations wherein it is desired to have the discharge chute extend centrally along the cutting apparatus traversal path, prior art workers (e.g. as in U.S. Pat. No. 3,452,530) have positioned the side-by side rotary blades in overlapping and necessarily meticulously synchronized rotary relationship. In the latter regard, each rotary blade is actuatably connected to a gearbox sheave and the respective gearbox sheaves are inter-connectably synchronized to prevent the overlapping rotary blades from colliding during the vegetation cutting operation. However, such gearbox synchronization means are deficient in that gearboxes and their inter-connected couplings are expensive and excessively noisy and in that the couplings have a tendency to malfunction which can result in severe collision damage to the rotary blades and to the gearbox parts. It is accordingly the general objective of the present invention to provide a housed vegetation cutting blades assembly that overcomes the disadvantages and deficiencies associated with prior art rotary blade assemblies.